<!DOCTYPE html>
<html>
<head lang="en">
  <meta charset="UTF-8">
  <title></title>
  <style>
    div{
      width: 4px;
      height: 200px;
      background-color: red;
      margin:100px auto;
      transform-origin: bottom center; /*变换中心*/
      animation:rot 30s steps(30) infinite;/* 调用动画*/
    }

    @keyframes rot {
      0%{
        transform:rotate(0deg);
      }

      100%{
        transform:rotate(360deg);
      }
    }
  </style>
</head>
<body>
  <div></div>
</body>
</html>